/*
 * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/StatusLine.java,v 1.14 2004/07/19 20:24:21 olegk Exp $
 * $Revision: 480424 $
 * $Date: 2006-11-29 06:56:49 +0100 (Wed, 29 Nov 2006) $
 *
 * ====================================================================
 *
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.commons.httpclient;

/**
 * Represents a Status-Line as returned from a HTTP server.
 * 
 * <a href="http://www.ietf.org/rfc/rfc2616.txt">RFC2616</a> states the
 * following regarding the Status-Line:
 * 
 * <pre>
 * 6.1 Status-Line
 * 
 *  The first line of a Response message is the Status-Line, consisting
 *  of the protocol version followed by a numeric status code and its
 *  associated textual phrase, with each element separated by SP
 *  characters. No CR or LF is allowed except in the final CRLF sequence.
 * 
 *      Status-Line = HTTP-Version SP Status-Code SP Reason-Phrase CRLF
 * </pre>
 * <p>
 * This class is immutable and is inherently thread safe.
 * 
 * @see HttpStatus
 * @author <a href="mailto:jsdever@apache.org">Jeff Dever</a>
 * @author <a href="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a>
 * @version $Id: StatusLine.java 480424 2006-11-29 05:56:49Z bayard $
 * @since 2.0
 */
public class StatusLine {

	// ----------------------------------------------------- Instance Variables

	/** The original Status-Line. */
	private final String statusLine;

	/** The HTTP-Version. */
	private final String httpVersion;

	/** The Status-Code. */
	private final int statusCode;

	/** The Reason-Phrase. */
	private final String reasonPhrase;

	// ----------------------------------------------------------- Constructors

	/**
	 * Default constructor.
	 * 
	 * @param statusLine
	 *            the status line returned from the HTTP server
	 * @throws HttpException
	 *             if the status line is invalid
	 */
	public StatusLine(final String statusLine) throws HttpException {

		int length = statusLine.length();
		int at = 0;
		int start = 0;
		try {
			while (Character.isWhitespace(statusLine.charAt(at))) {
				++at;
				++start;
			}
			if (!"HTTP".equals(statusLine.substring(at, at += 4))) {
				throw new HttpException("Status-Line '" + statusLine
						+ "' does not start with HTTP");
			}
			// handle the HTTP-Version
			at = statusLine.indexOf(" ", at);
			if (at <= 0) {
				throw new ProtocolException(
						"Unable to parse HTTP-Version from the status line: '"
								+ statusLine + "'");
			}
			this.httpVersion = (statusLine.substring(start, at)).toUpperCase();

			// advance through spaces
			while (statusLine.charAt(at) == ' ') {
				at++;
			}

			// handle the Status-Code
			int to = statusLine.indexOf(" ", at);
			if (to < 0) {
				to = length;
			}
			try {
				this.statusCode = Integer
						.parseInt(statusLine.substring(at, to));
			} catch (NumberFormatException e) {
				throw new ProtocolException(
						"Unable to parse status code from status line: '"
								+ statusLine + "'");
			}
			// handle the Reason-Phrase
			at = to + 1;
			if (at < length) {
				this.reasonPhrase = statusLine.substring(at).trim();
			} else {
				this.reasonPhrase = "";
			}
		} catch (StringIndexOutOfBoundsException e) {
			throw new HttpException("Status-Line '" + statusLine
					+ "' is not valid");
		}
		// save the original Status-Line
		this.statusLine = statusLine;
	}

	// --------------------------------------------------------- Public Methods

	/**
	 * @return the Status-Code
	 */
	public final int getStatusCode() {
		return statusCode;
	}

	/**
	 * @return the HTTP-Version
	 */
	public final String getHttpVersion() {
		return httpVersion;
	}

	/**
	 * @return the Reason-Phrase
	 */
	public final String getReasonPhrase() {
		return reasonPhrase;
	}

	/**
	 * Return a string representation of this object.
	 * 
	 * @return a string represenation of this object.
	 */
	public final String toString() {
		return statusLine;
	}

	/**
	 * Tests if the string starts with 'HTTP' signature.
	 * 
	 * @param s
	 *            string to test
	 * @return <tt>true</tt> if the line starts with 'HTTP' signature,
	 *         <tt>false</tt> otherwise.
	 */
	public static boolean startsWithHTTP(final String s) {
		try {
			int at = 0;
			while (Character.isWhitespace(s.charAt(at))) {
				++at;
			}
			return ("HTTP".equals(s.substring(at, at + 4)));
		} catch (StringIndexOutOfBoundsException e) {
			return false;
		}
	}
}
